08-29-2013, 01:04 PM
Salt (NaCl) is required by all mammalian species. The ions of sodium and also potassium (not atoms, ions are charged particles) are involved in the transport of electrical impulses between the nerve endings and hence are required for the body to function at all. It isn't a luxury - it's vital for the health of the animal (including us). I read somewhere that there was a Roman torture, whereby the victim was fed the most delicious meals, but devoid of any salt. Misery in the face of plenty. Even today, farmers will throw out lumps of salt into their fields for cattle to lick and animals in Africa will travel vast distances for a 'salt lick'.
Salt is also used as a preservative, and has been for thousands of years. Bacteria cannot live in high salt concentrations (or sugar, for that matter). Osmosis ensures that the water inside the bacterial cell membrane seeps out to try and dilute the concentrated solution on the other side of the cell wall. In effect, the cell dehydrates. One of the Celtic cultures is named for Hallstaat - literally, 'salt town'. Salt itself is not hygroscopic - although natural Rock Salt may appear to be. This, however, is due to the presence of either calcium or magnesium chlorides (or both), which are hygroscopic. Pure salt does not have this property of being able to attract moisture from the air.
I can well believe that Roman soldiers were once paid, at least in part, in salt. Food without it quickly becomes tasteless. It would also be vital if the soldier's unit was based some distance from the source of the salt. Transport costs would add to its value as a commodity. It has been suggested that the site of Rome itself was due to the fact that the set of hills that eventually became The Eternal City controlled passage along the coastal plain for the salt trade between Ostia and places further up and down the Italian peninsular.
Mike Thomas
(Caratacus)
Salt is also used as a preservative, and has been for thousands of years. Bacteria cannot live in high salt concentrations (or sugar, for that matter). Osmosis ensures that the water inside the bacterial cell membrane seeps out to try and dilute the concentrated solution on the other side of the cell wall. In effect, the cell dehydrates. One of the Celtic cultures is named for Hallstaat - literally, 'salt town'. Salt itself is not hygroscopic - although natural Rock Salt may appear to be. This, however, is due to the presence of either calcium or magnesium chlorides (or both), which are hygroscopic. Pure salt does not have this property of being able to attract moisture from the air.
I can well believe that Roman soldiers were once paid, at least in part, in salt. Food without it quickly becomes tasteless. It would also be vital if the soldier's unit was based some distance from the source of the salt. Transport costs would add to its value as a commodity. It has been suggested that the site of Rome itself was due to the fact that the set of hills that eventually became The Eternal City controlled passage along the coastal plain for the salt trade between Ostia and places further up and down the Italian peninsular.
Mike Thomas
(Caratacus)
visne scire quod credam? credo orbes volantes exstare.
